Modulation system



Feb; 17, 1931. M. OSNOS MODULATION SYSTEM Filed Oct. 22 1925 5 SOURCEINVENTOR MENDEL OSNQS TTORNEY Patented Feb. 17, 1931 UNITED STATESPATENT OFFICE MENDEL OSNOS, F BERLIN, GERMANY, ASSIGNOR TO GESELLSCHAFTFT TR DRAHT- LOSE TELEGRAPHIE M. B. H., OF BERLIN, GERMANY, ACORPORATION OF GER- MANY MODULATION SYSTEM Application filed October 22,1925, Serial No.

ductor with hooks 1 and 2, while B indicates a ferromagnetic substancesurrounding or coating the conductor. As can be seen, the flux linesflow in the way as just stated, that is to say, they only surround thisconductor. Of course, such a keying or telephony choker can be adaptedalso to any other con venient form of construction. For instance asshown by Fig. 2, a plurality of such conductors can be arranged inparallel, and can be passed by current in the same direction.

In this case the common feature may be regarded to reside in that themagnetic flux substantially surrounds but this one conductor, seeingthat the main flux passed through the iron. An especially importantfield of application for such conductors is in connection with theproduction of and action upon very short electromagnetic waves.

The view heretofore held was that, in order to diminish the losses thethickness of the ferro-magnetic layer should be chosen as small asfeasible. This arrangement is based upon the theory that in case wheresuch a conductor is to be used for the purposes of key- 5 'ing ortelephony, the aim should be to raise the iron losses as much aspossible, while the losses in the non-magnetic conductor should bereduced as far as feasible, for in this manner the modulation of atransmitter will be much more thorough and efficient. By the aid of thekeying and telephony choker, a resistance is cut in and out of theantenna or a consuming circuit. This resistance is made up of two parts,i. e., a constant resistance dependent upon the losses in thenon-magnetic conductor, and a variable portion residing in the lossesoccasioned in the ferro-magne-tic material. It can be seen therefromthat for best operation the constant part must be minimized as much aspossible, while the va- 64,245, and in Germany November 20, 1924.

riable part is to be raised to the greatest possible degree. By the keywork and the action upon a controlling choker, as is well known, avariation in the losses and the self-inductance is brought about.

Now, in accordance with the present invention the key and telephonychoker must be so dimensioned that the ratio between the change in lossresistance and the change in the selfinductance is made high. A suitableform of construction of the invention consists in that a good electricconductor, for instance, copper wire is enveloped by individual massivetubelets, the thickness of the iron layer comparatively to the thicknessof the conductor being chosen at such a ratio that the thickness of theiron layer amounts to over-1/20th of the diameter of the conductor. Inthe presence of such proportions the condition of relation betweenchange in the losses and change in the self-inductance is fulfilled.Instead of tubelets, also small iron disks could, if desired, beemployed, the thickness of these small disks having to be chosen so asmay be convenient. Under certain circumstances it may,for instance, besuitable to choose the thickness of these small disks at about 0.07 mm.In this case the iron losses consist substantially in hysteresis losses,whereas in the case of thicker disks the iron losses consists of bothhysteresis and eddy-current losses.

Another form of construction consists in that the non-magnetic conductoris wrapped with a heavy iron Wire.

Other advantages will be apparent in connection with the various figuresof the drawing in which:

Fig. 1 is an element of my arrangement.

Fig. 2 is a system in which it is used.

To further explain the applications of the present invention a diagramof connection is shown in Fig. 2 for a frequency-raising arrangementcomprising the use of a telephony or keying choker of the kind ashereinbefore described. Referring to the said figure G is the highfrequency generator, Al the circuit tuned to the generator frequency, T1a frequency changer by means of which the wave All is produced. T2 is afrequency changer for short waves by means of which multiplication towave A33 is produced. Connected with this circuit is the keying chokerconsisting of two parts D1 and D2 by Way of two condensers C1 and C2.The condensers are bridged by the keying or microphone or othermodulator circuit, the latter containing a modulator current source S.The condensers preclude the direct current, while they permit of thepassage of high frequency current, as

can be seen from tlie fig urje means of an.

additional transformer T3 multiplication of the frequency to the workingwave A99 is obtained. It is with this circuit that the antenna A isunited.

It is a recommendable plan to embed the keying or telephony chokerinto'a' refractory material such as concrete or asbestos, and to furtherenclose it inside an atmosphere poor in oxygen.

Having thus described my invention, what I claim is v I 1 In a highfrequency modulation system, a magnetic modulator, comprising, anelongated non-magnetic inductor core, and a sheath of magnetic materialenveloping said inductor core, said magnetic material being of athickness such that variations in imped ance due to variations in ironloss" substan tially exceed variations 1n= impedancedue to inductanceloss.

2. In a high frequency modulation system,-

a non-magnetic conductor having a ferromagnetic layer,said layer beingof such thickness that variations in the iron losses substa'ntiallyexceed the Variations in self-inductance during intervals" of keying,surrounding the said conductor, means for impressing high frequencycurrents on said conductor, and means for superposing direct currentsupon said conductor for modulating said high frequency currents'bycausing the losses in the ferro-magnetic material due to hysteresis andeddy currents to substantially exceed thenon-magnetic material losses.

3. In a high frequency modulation system; a non-magnetic conductor, asource of high frequency energy connected with said conductor, a layerof ferro-magnetic material enveloping said non-magnetic conductor, a:source of modulation currentconnected with said conductor forcontrolling the magnetic saturation of said ferro-magnetie material,means for superposing said modulating currents upon said high frequencycurrents in said conductor for modulating said high frequency currentspassing therethrough, said conductor having the enveloping layer offerro-magnetic material surrounding" the same of such thickness thatvariations in" the hysteresis and eddy current losses in the magneticmaterial, due to modulation currents impressed thereon, substantiallyexceed the variations in self-inductance during the periods ofmodulation of said high frequency current energy.

tance'of said non magnetic corei'n accordance with thesaturation thereofso as to modulate said high frequency current.

MENDEL osnos.

